r300/compiler: Standardize the number of bits used by swizzle fields

Swizzles are now defined everywhere as a field with 12 bits that contains
4 channels worth of meaningful information.  Any channel that is unused is
set to RC_SWIZZLE_UNUSED.  This change is necessary because rgb instructions
and alpha instructions were initializing channels that would never be used
(channel 3 for rgb and channels 1-3 for alpha) with 0 (aka RC_SWIZZLE_X).
This made it impossible to use generic helper functions for swizzles,
because sometimes a channel value of 0 meant unused and other times it
meant RC_SWIZZLE_X.

All hacks that tried to guess how many channels were relevant have
also been removed.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/mesa/drivers/dri/r300/compiler/radeon_compiler_util.h b/src/mesa/drivers/dri/r300/compiler/radeon_compiler_util.h
index 461ab9ffb1..dd0f6c6615 100644
--- a/src/mesa/drivers/dri/r300/compiler/radeon_compiler_util.h
+++ b/src/mesa/drivers/dri/r300/compiler/radeon_compiler_util.h
@@ -10,6 +10,8 @@ unsigned int rc_swizzle_to_writemask(unsigned int swz);
 
 rc_swizzle get_swz(unsigned int swz, rc_swizzle idx);
 
+unsigned int rc_init_swizzle(unsigned int initial_value, unsigned int channels);
+
 unsigned int combine_swizzles4(unsigned int src,
 			       rc_swizzle swz_x, rc_swizzle swz_y,
 			       rc_swizzle swz_z, rc_swizzle swz_w);
@@ -32,7 +34,7 @@ unsigned int rc_src_reads_dst_mask(
 		unsigned int dst_idx,
 		unsigned int dst_mask);
 
-unsigned int rc_source_type_swz(unsigned int swizzle, unsigned int channels);
+unsigned int rc_source_type_swz(unsigned int swizzle);
 
 unsigned int rc_source_type_mask(unsigned int mask);